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2021-10 Security Bulletin: Junos OS: SRX Series: Under a specific device configuration an attacker can access the devices J-Web management services from any interface, regardless of security settings protecting the service (CVE-2021-31384)



Article ID: JSA11252 SECURITY_ADVISORIES Last Updated: 13 Oct 2021Version: 1.0
Product Affected:
This issue affects Junos OS 20.4, 21.1. Affected platforms: SRX Series.

Due to a Missing Authorization weakness and Insufficient Granularity of Access Control in a specific device configuration, a vulnerability exists in Juniper Networks Junos OS on SRX Series whereby an attacker who attempts to access J-Web administrative interfaces can successfully do so from any device interface regardless of the web-management configuration and filter rules which may otherwise protect access to J-Web.

This issue affects:

Juniper Networks Junos OS SRX Series

  • 20.4 version 20.4R1 and later versions prior to 20.4R2-S1, 20.4R3;
  • 21.1 versions prior to 21.1R1-S1, 21.1R2.

This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.

The following minimal configuration is necessary:

[system services web-management http]


[system services web-management https]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

This issue has been assigned CVE-2021-31384.


The following software releases have been updated to resolve this specific issue: 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.2R1, and all subsequent releases.

This issue is being tracked as 1577816.

There are no viable workarounds for this issue other than disabling J-Web.
Software releases or updates are available for download at
Modification History:
2021-10-13: Initial Publication.
CVSS Score:
7.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N)
Severity Level:
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

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